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https://issues.apache.org/jira/browse/CASSANDRA-9591?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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mck updated CASSANDRA-9591:
---------------------------
    Attachment:     (was: 9591-2.0.txt)

> Scrub (recover) sstables even when -Index.db is missing
> -------------------------------------------------------
>
>                 Key: CASSANDRA-9591
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9591
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: mck
>            Assignee: mck
>              Labels: sstablescrub
>             Fix For: 2.0.x
>
>         Attachments: 9591-2.0.txt
>
>
> Today SSTableReader needs at minimum 3 files to load an sstable:
>  - -Data.db
>  - -CompressionInfo.db 
>  - -Index.db
> But during the scrub process the -Index.db file isn't actually necessary, 
> unless there's corruption in the -Data.db and we want to be able to skip over 
> corrupted rows. Given that there is still a fair chance that there's nothing 
> wrong with the -Data.db file and we're just missing the -Index.db file this 
> patch addresses that situation.
> So the following patch makes it possible for the StandaloneScrubber 
> (sstablescrub) to recover sstables despite missing -Index.db files.
> This can happen from a catastrophic incident where data directories have been 
> lost and/or corrupted, or wiped and the backup not healthy. I'm aware that 
> normally one depends on replicas or snapshots to avoid such situations, but 
> such catastrophic incidents do occur in the wild.
> I have not tested this patch against normal c* operations and all the other 
> (more critical) ways SSTableReader is used. i'll happily do that and add the 
> needed units tests if people see merit in accepting the patch.
> Otherwise the patch can live with the issue, in-case anyone else needs it. 
> There's also a cassandra distribution bundled with the patch 
> [here|https://github.com/michaelsembwever/cassandra/releases/download/2.0.15-recover-sstables-without-indexdb/apache-cassandra-2.0.15-recover-sstables-without-indexdb.tar.gz]
>  to make life a little easier for anyone finding themselves in such a bad 
> situation.



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